str1 = "hello world"
str2 = 'hello world'
str3 = '''hello
world'''

print(str1)
print(str2)
print(str3)
print('hel\'lo world') #\ 转义符
print('123---{0}---{1}---{2}'.format(4,5,6))
str1 = 'hello'
print(f'123---{str1}')

for i in range(0,101,2):
    print("===========开始下载==========")
    if i == 100:
        print("下载完成")
    else:
        # print(f'{i}%','[',"*"*(i//2),"."*((100-i)//2),']')
        str4 = "*" * (i//2) + "." * ((100-i) // 2)
        print(f'{i}%[{str4}]')